Polyesters and polyester containers having a reduced coefficient of friction and improved clarity

ABSTRACT

Polyesters and polyester containers having a reduced coefficient of friction and improved clarity are produced using an antiblock agent comprising a dried talc having from about 20 to about 300 ppm water or a fatty acid tethered talc. The use of these talcs result in polyesters and polyester containers having a coefficient of less than about 1.0 and a clarity with haze values of less than about 4%.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 60/280,295, filed Mar. 30, 2001, the disclosure of which isincorporated herein by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to polyesters and polyester containersand particularly to polyesters and polyester containers having a reducedcoefficient of friction and improved clarity.

2. Description of the Prior Art

Problems exist in conveving various types of polyester containers due tothe excessive amount of static friction encountered when containersurfaces contact. This excessive friction can lead to “process line” or“filling line” interruptions that are economically undesirable. Theproblem occurs after the polyester polymer has been molded into preformsor stretch blown into various types of containers. The containers aresometimes conveyed directly into a palletizing station and then shippedto a filling plant or they are conveyed to a labeling and filling linecontained within the same plant. This problem is more pronounced in thecarbonated soft-drink (“CSD”) industry due to the high speed ofstretch-blow molding conveying and filling lines. The problem is alsoencountered in other parts of the polyester container industry where thecontainers are being conveyed under pressures applied from congestedareas of the conveying process.

During the process of blow molding or injection molding containerpreforms, the preforms are fed into a large box (gaylord box) that holdsmore than 1000 preforms. Given the high coefficient of friction (“COF”)that is common between polyester surfaces, the preforms tend to stack ontop of one another in a conical shape as viewed from the side of thebox. This stacking results in fewer preforms being loaded into a box andtherefore higher shipping costs per preform. The high level of frictionbetween the preform surfaces can also cause jams in the feeder bin asthe preforms are loaded onto the feed rail. Similarly, jams may alsooccur on the feed rail due to such friction.

Straight-walled containers such as the two liter bottles used in thecarbonated soft-drink (“CSD”) industry have a very smooth surface thatmaximizes the amount of surface area that comes in contact between twoadjacent bottles. With the inherently high COF of polyester containerssuch as PET (PET has a static COF greater than 1.0), the containersbecome entangled and “tip over” or just stop moving in the conveyingline after blowing or during filling. Such tip over and stopageobviously causes undesirable disruptions in the conveying or fillingprocess.

A high COF prevents adjacent containers on a multiple-row conveying linefrom moving (turning or slipping) during conveying. When the conveyingline changes direction, sometimes as much as 90 degrees, the containersmay become entangled and either stay upright and stop the feed or tipover and stop the line. In either event, someone has to monitor theseproblem areas at all times to keep the line moving. Therefore, acontainer having a low static COF that could slide and rotate againstother containers during conveying would minimize or eliminate processdowntime and the need for someone to constantly monitor the process.These problems are all related to polyesters having an unacceptably COF.

There is prior art relating to methods for reducing the COF forpolyesters. One such method involves the addition of an antiblock agentssuch as silica, talc, calcium carbonate, calcium stearate, and otherinorganic compounds. JP 9272191 discloses a multi-layer sheet containinginert particulates (10 to 5000 ppm at 0.5 to 30 micron size) includingsilica and talc used to improve the slip properties, scratch resistance,cut properties and adhesive properties of the sheet and articles madefrom the sheet. U.S. Pat. No. 5,840,419 discloses multilayer polyolefinfilms that use cross-linked silicone in combination with inorganicantiblock agents such as talc in amounts of 500 to 5000 ppm withparticles sizes from 1 to 6 micrometers to reduce the COF. Neitherreference discloses stretch blow molded containers. U.S. Pat. No.6,323,271 discloses polyester resins containing a silica selected fromthe group consisting of fumed silica, colloidal silica and silica beadsthat is useful for making containers having reduced stickiness relativeto containers made from the same resin but without the silica. U.S. Pat.No. 5,258,161 discloses polyolefin films having talc in amounts of 0.05%to 3% by weight as an antiblock agent. U.S. Pat. No. 5,908,890 disclosea polymer film comprising a polyolefin matrix containing a pumiceantiblock agent in amounts of less than about 1 percent by weight.

U.S. Pat. No. 5,830,544 discloses poly(ethyleneterephthalate) (“PET”)bottles having reduced stickiness due to the addition of amorphoussilica at a concentration range of 10 to 100 ppm. The use of additivesother than amorphous silica and methods for improving clarity of thebottle containing anti-stick additives are not disclosed. JP PatentApplication Heisei 2-307117 discloses the optimization of loading andparticulate size of the antiblock on film properties such as haze andCOF. The reference does not disclose containers such as plastic bottlesnor does it disclose drying an antiblock before processing.

JP Patent Application Heisei 4-180957 discloses mono- and multi-layersheet and thermoformed moldings formed from PET having 100 to 10,000 ppmtalc with particle size less than 10 microns. Suitable thermoformedcontainers include blister packs that have good clarity. Containers suchas plastic bottles, the benefits of drying the antiblock beforeprocessing, and the use of fatty acid tethers are not disclosed.

There is prior art relating to polyester films incorporating a varietyof inorganic particles to improve crystallinity and slip. JP 7238211discloses magnetic tape; JP 6065478 discloses magnetic tape, photograph,packaging film; JP5104621 discloses thermoformed sheets; JP 4183718discloses base film for magnetic tape, photographic film, electricalinsulating film, a base material for gold yarn, and packaging material;and JP 4180957 discloses PET w/talc with good slipping and stackingproperties with good transparency.

None of the prior art references disclose polyesters or polyestercontainers having a coefficient of friction of much less than 1.0,particularly polyesters or polyester containers having talc as anantiblock agent. There is, therefore, a need for new and improvedpolyesters and polyester containers having a reduced COF, particularlyhigh clarity (low haze) containers that have a reduced COF.

SUMMARY OF THE INVENTION

It is, therefore, an object of the invention to provide polyesters andpolyester containers having a reduced coefficient of friction andacceptable clarity.

It is another object of the invention to provide polyesters andpolyester containers having a reduced coefficient of friction andenhanced clarity.

It is a further object of the invention to provide antiblock agentsuseful in the production of polyester and polyester containers havingacceptable and enhanced clarity.

It is another object of the invention to provide an antiblock agentuseful in the production of polyester and polyester containers.

These and other objects are achieved using a dried talc having fromabout 20 to about 300 ppm water or a fatty acid tethered talc to reducethe coefficient of friction for polyesters and polyester containers. Theuses of these talcs result in polyesters and polyester containers havinga coefficient of less than about 1.0 and a clarity with haze values ofless than about 4%. Such polyesters and polyester containers can be usedto package various foods and beverages.

Other and further objects, features and advantages of the presentinvention will be readily apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the effect of talc particle size on COF.

FIG. 2 is a graph showing the effect of talc particle size on haze.

FIG. 3 is a graph showing the effect of BaSO₄ particle size on COF.

FIG. 4 is a graph showing the effect of BaSO₄ particle size on haze.

FIG. 5 is a graph showing the effect of SiO₂ particle size on COF.

FIG. 6 is a graph showing the effect of SiO₂ particle size on haze.

FIG. 7 is a graph comparing the effect of talc, BaSO₄ and SiO₂ on COF.

FIG. 8 is a graph comparing the effect of talc, BaSO₄ and SiO₂ on haze.

FIG. 9 is a graph comparing the effect of dried and undried talc on COF.

FIG. 10 is a graph comparing the effect of dried and undried talc onhaze.

DETAILED DESCRIPTION OF THE INVENTION

The term “weight percentages” and the acronym “wt %” as used hereinrefer to weight percentages based on the total weight of the polyestercomposition in its final form with all ingredients added.

The term “container” as used herein includes containers and the performsused to manufacture the containers.

In one aspect, the present invention provides polyesters and polyestercontainers having a reduced coefficient of friction (“COF”) andacceptable clarity. The reduced COF is obtained by adding talc, ahydrated magnesium silicate with the chemical formula Mg₃Si₄ O₁₀ (OH)₂,to the polyesters. The talc, or antiblock agent, creates a surfaceroughness that decreases the COF of the polyester while not adverselyaffecting the clarity of the polyester or polyester container.

The talc useful in the present invention comprises about 62 wt % SiO₂and about 31% MgO, has a density of about 2.7 grams per cubic centimeter(g/cc), and average particle sizes of from about 0.05 to about 50microns, preferably from about 0.1 to about 20 microns, most preferablyfrom about 0.2 to about 10 microns. Suitable talc is commerciallyavailable from several sources, including Polar Minerals, Inc., 2005Newpoint Place Parkway, Lawrenceville, Ga. 30043, under the name PolarTalc 9107 or 9103 (with or without fatty acid tether attached).

Before addition to the polyester, the talc is dried so that it containsfrom about 20 to about 300 ppm water, preferably from about 50 to about250 ppm water. The use of this “dried talc” is critical to this aspectof the present invention because it permits the production of apolyester with a combination of the maximum reduction in the COF andminimum adverse affect on clarity and haze. The talc can be dried byconventional means, such as a dryer or oven under conditions that areknown to skill artisans. If the talc is not dried, a higher loading ofthe talc will be required. If the talc is not dried, the level of hazeacquired for a certain amount of friction reduction will be increased.

The concentration of dried talc in the polyesters of the presentinvention is from about 0.001 to about 0.1 wt %. Because the clarity ofthe container decreases with increasing talc concentration, thepreferred concentration is from about 0.001 to about 0.05 wt %, mostpreferably from about 0.005 to about 0.025 wt %.

The polyesters and polyester containers made according to this aspect ofpresent invention have a coefficient of friction of from about 0.01 toabout 1.0.

The polyesters and polyester containers made according to this aspect ofpresent invention have an acceptable clarity with haze values of fromabout 0.1 to about 4%, preferably from about 0.1 to about 3%.

Other well known antiblock agents useful in the production of polyestersand polyester containers and having properties similar to talc willperform equally well in the present invention when dried so that theycontain from about 20 to about 300 ppm water, e.g., amorphous silica,barium sulfate, zinc stearate, calcium phosphate, and mixtures thereof.

In a further aspect, the present invention provides polyesters andpolyester containers having a reduced coefficient of friction (“COF”)and enhanced clarity. The clarity of the polyesters and polyestercontainers is enhanced by treating the talc with a fatty acid to attacha tether on the talc (“tethered talc”).

Fatty acids useful in the present invention are fatty acids that arecompatible with the polyesters and thermally stable at the selectedpolymerization and/or processing conditions used to make the polyestersand polyester containers. Preferred fatty acids are selected from thegroup consisting of branched stearic acid, C₆ to C₂₀ saturated andunsaturated, linear and branched, fatty acids. Most preferred fattyacids are linolic, palmitic, oleic, linoleic, and palmolenic fattyacids.

The talc useful to produce tethered talc is “undried talc” availablecommercially or “dried talc” produced as described herein. The talc istethered to the fatty acid by conventional means well known to skilledartisans. Such fatty acid tethered talcs are also commercially availablefrom several sources including Polar Minerals, Inc., 2005 Newpoint PlaceParkway, Lawrenceville, Ga. 30043.

Although not bound by theory, it is believed that the fatty acids makethe talc more compatible with the polyester and reduce voids uponorientation of the polymer. Voids are caused by incompatibility of thepolyester at the interface with the talc. When a container is stretched,if the polyester is not compatible with the talc particulate, it pullsaway and creates a void. The organic fatty acid tethers act as a liaisonbetween the inorganic talc particulate and the polyester.

The concentration of tethered talc in the polyesters of the presentinvention is from about 0.001 to about 0.1 wt %. Because less tetheredtalc is needed generally, the preferred concentration is from about0.001 to about 0.04 wt %, most preferably from about 0.005 to about0.020 wt %.

The polyesters and polyester containers made according to this aspect ofpresent invention have a coefficient of friction of from about 0.01 toabout 1.0.

The polyesters and polyester containers made according to this aspect ofpresent invention have an enhanced clarity with haze values of fromabout 0.1 to about 3%, preferably from about 0.1 to about 2%.

The tethered talc is added to polyesters during the production processto produce polyesters and polyester containers having a reducedcoefficient of friction and enhanced clarity.

The talc and the tethered talc can be added to the polyester during thepolymerization process or it can be pre-blended with a polyester beforeprocessing to form a concentrate. The concentrate can then be mixed withvirgin polyester to achieve the desired concentration of talc ortethered talc. Mixtures of dried talc and tethered talc (tethered talcmade with dried or undried talc) are embodiments of the presentinvention.

The polyesters of the present invention can be made using processes wellknown to skilled artisans. Suitable polyesters can be produced in aconventional manner by the reaction of a dicarboxylic acid having 2 to40 carbon atoms with polyhydric alcohols such as glycols or diolscontaining from 2 to about 20 carbon atoms. The processes for producingpolyesters, including process conditions, catalysts, sequesteringagents, quenching agents, and additives, are known to skilled artisans.Methods of producing polyester materials and combinations of polyesterswith other polymeric materials are given in W. R. Sorenson and T. W.Campbell, “Preparative Methods of Polymer Chemistry,” (IntersciencePublishers, New York 1968, and subsequent editions) and the“Encyclopedia of Polymer Science; and Engineering, 2nd Ed.,” H. F. Market al., (John Wiley & Sons, New York 1985), particularly Volume 12,pages 1-290 (polyesters generally) and especially pages 259-274 forresin manufacturing processes.

The dicarboxylic acid for producing the polyester is an alkyldicarboxylic acid having 2 to 20 carbon atoms, or an aryl- oralkyl-substituted aryl dicarboxylic acid containing from 8 to 16 carbonatoms. Additionally, an alkyl dicarboxylic acid diester having from 4 to20 carbon atoms or an alkyl-substituted aryl dicarboxylic acid diesterhaving from 10 to 20 carbon atoms can be utilized instead of thedicarboxylic acid. Polyhydric glycols or diols containing from 2 to 8carbon atoms are preferred, most preferably ethylene glycol. Glycol ordiol ethers having from 4 to 12 carbon atoms may be substituted for theglycol or diol.

Terephthalate polyesters are made from either dimethyl terephthalate orterephthalic acid with ethylene glycol or from either dimethylterephthalate or terephthalic acid with 1,4-cyclohexane diol. Suitabledicarboxylic acids include terephthalic acid, isophthalic acid, malonic,succinic, glutaric, adipic, suberic, sebacic, maleic and fumaric acid,all of which are well known dicarboxylic acids, or mixtures of thesesuch that a copolyester is produced. Suitable glycols, in addition toethylene glycol and 1,4-cyclohexane diol, include propylene glycol,1,3-propanediol, glycerol, 1,2-butanediol, 1,4-butanediol,pentaerythritol, neopentylglycol, similar glycols and diols, andmixtures thereof. These compounds and the processes for makingpolyesters and copolyesters using the compounds are all well known inthe art.

Conventional production of polyethylene terephthalate (and otherpolyesters such as other terephthalate, isophthalate and mixedterephthalate-isophthalate polyesters) comprises reacting terephthalicacid or dimethyl terephthalate with ethylene glycol at a temperature ofabout 200° C. to about 250° C. to form monomers and water (or methanol).Because the reaction is reversible, the water (or methanol) iscontinuously removed to drive the reaction to the production of monomer.Next, the monomer undergoes a polycondensation reaction to form thepolymer. During the reaction of the terephthalic acid or dimethylterephthalate and ethylene glycol, it is not necessary to have acatalyst present although it may be advantageous to do so to increasethe rate of reaction. Generally, during the polycondensation reaction,the use of a catalyst is preferred, for example, antimony compounds orother catalyst known to those skilled in the art. In the making ofbottle preforms and plastic bottles from the preforms, it is desirableto produce the cleanest, clearest polymer. Generally, the less additivesemployed, the clearer the polymer produced. Conversely, it is sometimesdesirable to make a colored plastic bottle which means that the bottlepreform may also be colored. Accordingly, various pigments, dyes,fillers and other substances known to those skilled in the art may beadded to the polymer, generally during or near the end of thepolycondensation reaction. The specific additives used and the point ofintroduction during the reaction is known in the art and does not form apart of the present invention. Any conventional system may be employedand those skilled in the art can pick and choose among the varioussystems for the introduction of additives to select the best for thedesired result.

The polyester containers of the present invention can be made using wellknown processes for producing containers from polyesters. Such processesinclude injection stretch blow molding and extrusion blow molding.Preferably, such containers are bottles made using a conventional blowmolding process well known to skilled artisans.

In another aspect, the present invention provides antiblock agentsuseful in the production of polyester and polyester containers in theform of talc that has been dried to contain from about 20 to about 300ppm water. The talc can be treated by any conventional method forremoving water but is preferably dried in a conventional oven. The talcis added to polyesters during the production process to producepolyesters and polyester containers having a reduced coefficient offriction and acceptable clarity.

In a further aspect, the present invention provides antiblock agentsuseful in the production of polyester and polyester containers in theform of dried talc that has been treated with fatty acids to produce atethered talc.

Suitable polyesters useful in the present invention are well known inthe art and are generally formed from repeat units comprisingterephthalic acid, dimethyl terephthalate, isophthalic acid, dimethylisophthalate, dimethyl-2,6-naphthalenedicarboxylate,2,6-naphthalenedicarboxylic acid, ethylene glycol, diethylene glycol,1,4-cyclohexane-dimethanol, 1,4-butanediol, and mixtures thereof.

The dicarboxylic acid component of the polyester may optionally bemodified with up to about 15 mole percent of one or more differentdicarboxylic acids. Such additional dicarboxylic acids include aromaticdicarboxylic acids preferably having 8 to 14 carbon atoms, aliphaticdicarboxylic acids preferably having 4 to 12 carbon atoms, orcycloaliphatic dicarboxylic acids preferably having 8 to 12 carbonatoms. Examples of dicarboxylic acids to be included with terephthalicacid are: phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylicacid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid,diphenyl-4,4′-dicarboxylic acid, succinic acid, glutaric acid, adipicacid, azelaic acid, sebacic acid, mixtures thereof and the like.

In addition, the glycol component may optionally be modified with up toabout 15 mole percent, of one or more different diols other thanethylene glycol. Such additional diols include cycloaliphatic diolspreferably having 6 to 20 carbon atoms or aliphatic diols preferablyhaving 3 to 20 carbon atoms. Examples of such diols include: diethyleneglycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol,butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol,3-methylpentanediol-(2,4), 2-methylpentanediol-(1,4),2,2,4-trimethylpentane-diol-(1,3), 2-ethylhexanediol-(1,3),2,2-diethylpropane-diol-(1,3), hexanediol-(1,3),1,4-di-(hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane,2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane,2,2-bis-(3-hydroxyethoxyphenyl)-propane,2,2-bis-(4-hydroxypropoxyphenyl)-propane, mixtures thereof and the like.Polyesters may be prepared from two or more of the above diols.

The preferred polyesters of the present invention arepoly(ethyleneterephthalate) (PET”), poly(ethylenenaphthalate) (“PEN”),poly(ethyleneisophthalate) (“PIT”), andpoly(ethylenebutyleneterephthalate), with PET being the most preferred,most preferably poly(ethyleneterephthalate) (“PET”).

The polyester may also contain small amounts of trifunctional ortetrafunctional comonomers such as trimellitic anhydride,trimethylolpropane, pyromellitic dianhydride, pentaerythritol, and otherpolyester forming polyacids or polyols generally known in the art.

Also, although not required, other additives normally used in polyestersmay be added to the polyester. Such additives include, but are notlimited to colorants, toners, pigments, carbon black, glass fibers,fillers, impact modifiers, antioxidants, stabilizers, flame retardants,reheat aids, acetaldehyde reducing compounds, oxygen scavengers, barrierenhancing aids and the like.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof, although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

EXAMPLES 1 THROUGH 51

The antiblock agents Ba₂SO₄, talc, and SiO₂were added to PET CB-12(CB-12 is a copolyester of terephthalic acid, isophthalic acid, andethylene glycol commercially available from Eastman Chemical Company asESTAPAK® CSC Resin) at concentrations of 0.0125 to 0.10 wt % withparticle sizes ranging from 20 nanometers to 7 microns. The “undried”antiblock agents were incorporated into the PET in the form ofconcentrates made by two processes: (1) melt blending on a twin screwextruder into a 1.0 wt % concentrate (“SC/MB”) and (2) in situ in thePET preparation to make a 1.0 wt % concentrate (“MBC/MB”). Both methodswere evaluated in PET bottles by injection molding pellet/pellet blendson an eight cavity Husky injection molding machine to make 2-literpreforms. The resulting preforms were stretch blown on a SIDEL 2/3stretch blow molding machine into 2-liter bottles. The bottles wereanalyzed for their haze level (sidewall haze was measured using ASTMD-1003) and for coefficient of friction by mounting two bottlesperpendicular and in contact with each other, turning one bottle andmeasuring torque required to turn the second bottle. The coefficient offriction was calculated as μ=(Torque/R)/F₂, where Torque is the outputof the torque-sensing device, R is the bottle radius, and F₂ is theactual load or force experienced by the bottles at their contact point.The results are shown in Tables 1, 2, and 3 and FIGS. 1 through 8. FIGS.1 through 6 are graphs comparing the haze, COF, loadings, and particlesizes of the samples. Referring to the Tables and Figures, a comparisonof the data show that the polyesters and polyester containers madeaccording to the present invention have a reduced coefficient offriction and acceptable clarity.

FIG. 7 shows that the resulting COF's are very similar for a givenloading of antiblock. Comparison of bottle sidewall haze is shown inFIG. 8. The results show that containers made using the talc have a havea slightly higher clarity when compared to containers made using SiO₂and Ba₂SO₄. TABLE 1 Coefficient of Friction for PET/Talc Blends Side-Prep Particle Bottle COF wall Ex. # Polymer Method size (μ) wt % AveStdev Haze 1 CB-12 SC./MB 0.2 0.0125 0.633 0.063 1.62 2 CB-12 SC./MB 0.20.025 0.487 0.042 3.22 3 CB-12 SC./MB 0.2 0.05 0.415 0.059 7.01 4 CB-12SC./MB 0.2 0.1 0.372 0.029 12.54 5 CB-12 SC./MB 7 0.0125 0.827 0.0741.84 6 CB-12 SC./MB 7 0.025 0.425 0.029 4.08 7 CB-12 SC./MB 7 0.05 0.4110.068 7.25 8 CB-12 SC./MB 7 0.1 0.360 0.036 13.96 9 CB-12 MBC/MB 70.0125 0.953 0.200 2.71 10 CB-12 MBC/MB 7 0.025 0.575 0.018 4.58 11CB-12 MBC/MB 7 0.05 0.516 0.070 8.43 12 CB-12 MBC/MB 7 0.1 0.485 0.05314.22

TABLE 2 Coefficient of Friction for PET/BaSO₄ Blends Prep Particle COF %Haze Example Polymer Method Size (μ) wt % BaSO₄ (Ave of 4 sets)(Measured) 13 CB-12 — 0 1.443 1.07 CB-12/PP 14 PET SC/MB — 0 1.617 0.715 CB-12 SC/MB <1 0.0125 1.136 4.53 16 CB-12 SC/MB <1 0.025 0.649 8.8517 CB-12 SC/MB <1 0.05 0.397 14.5 18 CB-12 SC/MB <1 0.1 0.345 33.35 19CB-12 SC/MB 3 0.0125 0.731 2.8 20 CB-12 SC/MB 3 0.025 0.413 5.83 21CB-12 SC/MB 3 0.05 0.270 9.16 22 CB-12 SC/MB 3 0.1 0.247 14.54 23 CB-12SC./MB 1 0.0125 0.996 4.22 24 CB-12 SC/MB 1 0.025 0.467 9.76 25 CB-12SC/MB 1 0.05 0.328 16.12 26 CB-12 SC/MB 1 0.1 0.320 30.56 27 CB-12MBC/MB <1 0.0125 1.076 3.67 28 CB-12 MBC/MB <1 0.025 0.840 7.95 29 CB-12MBC/MB <1 0.05 0.355 14.64 30 CB-12 MBC/MB <1 0.1 0.282 25.08 31 CB-12MBC/MB 3 0.0125 0.714 4.17 32 CB-12 MBC/MB 3 0.025 0.294 6.89 33 CB-12MBC/MB 3 0.05 0.224 12.57 34 CB-12 MBC/MB 3 0.1 0.189 24.08 35 CB-12MBC/MB 1 0.0125 0.973 4.89 36 CB-12 MBC/MB 1 0.025 0.479 9.42 37 CB-12MBC/MB 1 0.05 0.282 14.05 38 CB-12 MBC/MB 1 0.1 0.268 25.06

TABLE 3 Coefficient of Friction for PET/SiO₂ Blends SiO₂ PartSize BottleCOF % Haze Example Polymer Prep Method (μ) wt % SiO₂ Ave Stdev (ASTMD-1003) 39 CB-121 none — 0 1.443 0.061 1.07 40 CB-12 SC/MB 0.02 0.01251.536 0.191 1.34 41 CB-12 SC/MB 0.02 0.025 1.348 0.148 1.55 42 CB-12SC/MB 0.02 0.05 1.090 0.092 2.15 43 CB-12 SC/MB 0.02 0.1 0.932 0.1435.94 44 CB-12 SC/MB 5 0.0125 0.760 0.260 5.28 45 CB-12 SC/MB 5 0.0250.362 0.079 9.95 46 CB-12 SC/MB 5 0.05 0.324 0.058 20.31 47 CB-12 SC/MB5 0.1 0.278 0.022 33.53 48 CB-12 MBC/MB 5 0.0125 0.674 0.088 4.3 49CB-12 MBC/MB 5 0.025 0.317 0.080 8.34 50 CB-12 MBC/MB 5 0.05 0.293 0.05712.3 51 CB-12 MBC/MB 5 0.1 0.278 0.023 20.72

EXAMPLES 52 THROUGH 63

Polar talc 9107 (7 micron) was dried to approximately 250 ppm moistureand then added to a PET reaction mixture at a loading of 1.0 wt %. Theresulting concentrate was used to make blends as described in Example 1.The resulting COF and haze (measured using ASTM D-1003) were determinedon the bottles and bottle sidewalls, respectively. Coefficient offriction was measured by mounting two bottles perpendicular and incontact with each other, turning one bottle and measuring torquerequired to turn the second bottle. The coefficient of friction wascalculated as μ=(Torque/R)/F₂, where Torque is the output of thetorque-sensing device, R is the bottle radius, and F₂ is the actual loador force experienced by the bottles at their contact point. The resultsare shown in Table 4 (COF is an average of 4 tests and % Haze is anaverage of 3 tests). When compared to bottles prepared with “undried”talc (Examples 61, 62, and 63), the results shown graphically in FIG. 9show that a significant improvement in bottle sidewall COF was obtainedat similar loadings when using the “dried” talc. FIG. 10 shows that asignificant improvement in % haze was obtained at similar loadings whenusing the “dried” talc. TABLE 4 Example wt % Talc Talc, Dried or UndriedCOF % Haze 52 0 Control Sample 1.28 1.04 53 0.01 Dried 0.35 2.23 540.015 Dried 0.25 3.55 55 0.02 Dried 0.26 3.23 56 0.025 Dried 0.22 4.7357 0.03 Dried 0.22 4.95 58   0 (repeat) Control Sample 1.19 0.96 59 0.01(repeat) Dried 0.27 2.21 60 0 Control Sample 1.443 1.070 61 0.0125Undried 0.827 1.62 62 0.025 Undried 0.425 3.22 63 0.05 Undried 0.4117.01

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims. Obviously many modifications and variations ofthe present invention are possible in light of the above teachings. Itis therefore to be understood that within the scope of the appendedclaims the invention may be practiced otherwise than as specificallydescribed.

1-21. (canceled)
 22. A method for making a polyester polymer, comprising blending about 0.001 to about 0.1 wt % antiblocking agent containing from about 20 to about 300 ppm water with a polyester polymer, and forming a polyester polymer having a coefficient of friction from about 0.01 to about 1.0.
 23. The method of claim 22, wherein the method comprises blending about 0.001 to about 0.05 wt % antiblocking agent with said polyester polymer.
 24. The method of claim 22, wherein the method comprises blending about 0.001 to about 0.02 wt % antiblocking agent with said polyester polymer.
 25. The method of claim 22, wherein the polyester polymer produced has a haze value of from about 0.1% to about 4%.
 26. The method of claim 22, wherein the polyester polymer produced has a haze value of from about 0.1% to about 3%.
 27. The method of claim 22, wherein the polyester polymer produced has a haze value of from about 0.1% to about 2%.
 28. The method of claim 22, wherein the antiblocking agent is selected from the group consisting of amorphous silica, barium sulfate, zinc stearate, calcium phosphate, talc and mixtures thereof.
 29. The method of claim 26, wherein the antiblocking agent is talc having an average particle size of from about 0.2 microns to about 10 microns.
 30. The method of claim 22, wherein the polyester polymer produced comprises poly(ethyleneterephthalate), poly(ethylenenaphthalate), poly(ethyleneisophthalate), or poly(ethylenebutyleneterephthalate).
 31. The method of claim 22, wherein the polyester polymer produced comprises poly(ethyleneterephthalate).
 32. A method for making a concentrate, comprising blending antiblocking agent containing from about 20 to about 300 ppm water with a polyester polymer to form a concentrate, wherein said concentrate is useful for making a polyester polymer having a coefficient of friction from about 0.01 to about 1.0.
 33. A method for making a polyester polymer, comprising blending antiblocking agent containing from about 20 to about 300 ppm water with a polyester polymer to form a concentrate, and then blending said concentrate with a virgin polyester polymer to form a polyester polymer having a coefficient of friction from about 0.01 to about 1.0.
 34. The method of claim 33, wherein said polyester polymer having a coefficient of friction from about 0.01 to about 1.0 has a final concentration of about 0.001 to about 0.05 wt % antiblocking agent.
 35. The method of claim 33, wherein said polyester polymer having a coefficient of friction from about 0.01 to about 1.0 has a final concentration of about 0.001 to about 0.02 wt % antiblocking agent.
 36. The method of claim 33, wherein said polyester polymer having a coefficient of friction from about 0.01 to about 1.0 has a haze value of from about 0.1% to about 4%.
 37. The method of claim 33, wherein said polyester polymer having a coefficient of friction from about 0.01 to about 1.0 has a haze value of from about 0.1% to about 3%.
 38. The method of claim 33, wherein said polyester polymer having a coefficient of friction from about 0.01 to about 1.0 has a haze value of from about 0.1% to about 2%.
 39. The method of claim 33, wherein the antiblocking agent is selected from the group consisting of amorphous silica, barium sulfate, zinc stearate, calcium phosphate, talc and mixtures thereof.
 40. The method of claim 39, wherein antiblocking agent is talc having an average particle size of from about 0.2 microns to about 10 microns.
 41. The method of claim 33, wherein the polyester polymer having a coefficient of friction from about 0.01 to about 1.0 comprises poly(ethyleneterephthalate), poly(ethylenenaphthalate), poly(ethyleneisophthalate), or poly(ethylenebutyleneterephthalate).
 42. The method of claim 33, wherein the polyester polymer having a coefficient of friction from about 0.01 to about 1.0 comprises poly(ethyleneterephthalate). 